The neurophysiology of unmyelinated tactile afferents.
CT (C tactile) afferents are a distinct type of unmyelinated, low-threshold mechanoreceptive units existing in the hairy but not glabrous skin of humans and other mammals. Evidence from patients lacking myelinated tactile afferents indicates that signaling in these fibers activate the insular cortex. Since this system is poor in encoding discriminative aspects of touch, but well-suited to encoding slow, gentle touch, CT fibers in hairy skin may be part of a system for processing pleasant and socially relevant aspects of touch. CT fiber activation may also have a role in pain inhibition. This review outlines the growing evidence for unique properties and pathways of CT afferents.
Olausson
Håkan
H
Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden. olausson@physiol.gu.se
Wessberg
Johan
J
Morrison
India
I
McGlone
Francis
F
Vallbo
Ake
A
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology / Q000503:physiopathology; D006197:Hair / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008465:Mechanoreceptors / Q000502:physiology; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D009619:Nociceptors / Q000473:pathology / Q000502:physiology; D014110:Touch / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*